They say a man's house is his castle, so why shouldn't he be comfortable in it? Jack Lemmon has the right idea in this shot from 1966. And no, we're not talking about the cigar he's puffing on so confidentially. We're referring to those Prince Albert slippers that he's got on his feet. These aren't your grandmother's baby-blue plush slippers — these are classic house slippers, the kind that English lords popularized centuries ago during lavish events at their estates.

These men, like Lemmon, knew that it's perfectly acceptable to ditch your leather-soled shoes once you cross your threshold. Yet, at the same time, going barefoot in front of company is nothing short of gauche. And so, the slipper is the solution — an easy-to-wear middle ground that is almost more elegant (and certainly more personal) than a traditional hard-bottomed shoe.

Unlike his royal predecessors, who strictly donned slippers with their evening-wear, Lemmon is showing that a slipper worn with a casual outfit is just as appropriate in this day and age. Wear 'em next time you have some friends over with a simple pair of jeans and a button-down, and you'll look like the king of your own castle. Just do yourself a favor and lose those socks.